Illuminating device for an operating microscope

ABSTRACT

The present invention relates to an illuminating device for an operating microscope including two observation beam paths for a first observer and two observation beam paths for a second observer. An illuminating system provides two parallel illuminating beam paths and a deflecting device, for deflecting the parallel illuminating beam paths onto an object that is to be observed. The deflecting device includes a first semitransparent deflector element which is associated with a first observation beam path of the first observer and a first observation beam path of the second observer, and a second semitransparent deflector element, which is associated with a second observation beam path of the first observer and a second observation beam path of the second observer. The first illuminating beam path acts exclusively on the first deflector element and the second illuminating beam path acts exclusively on the second deflector element.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of the German patent application 102010 003 295.6 filed Mar. 25, 2010, the entire disclosure of which isincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to an illuminating device for an operatingmicroscope of a type having two observation beam paths for a firstobserver (main surgeon) and two observation beam paths for a secondobserver (assistant), and to a stereomicroscope of a type having a mainobjective and a magnification system downstream from the main objective.

BACKGROUND OF THE INVENTION

Illuminating devices for operating microscopes generally use anilluminating beam path which is at an angle in the region of about 6° tothe observation beam path (so-called 6° illumination). This avoids theundesirable shadowing which would occur at larger angles between theobservation beam path and the illuminating beam path.

Eye surgery places additional special demands on the illumination of amicroscope. To start with, a sufficiently plastic image is obtained atan illuminating angle of, again, about 6°. However, for certainophthalmic observations or interventions it is necessary to produce theso-called red reflex. In this, the pupil of the eye being operated onshines reddish as a result of the light refracted by the retina. Thismethod of illumination is of great importance in cataract operations,for example, as tissue residues show up particularly well in thecounter-light of the red reflex. The production of the red reflexrequires smaller angles between the observation beam path and theilluminating beam path, the angles preferably being in the range from 0°to 2° (so-called 0° or 2° illumination).

Operating microscopes which are configured with two pairs ofstereoscopic observation beam paths for a first observer (main surgeon)and a second observer (assistant), respectively, often have thedisadvantage that the red reflex is very easy for the main surgeon tosee but cannot be seen satisfactorily by the co-observer. The latterwill only see a good red reflex in one of his two observation channels,depending on his position, either to the right or left of the mainsurgeon. This has an adverse effect on stereoscopic viewing.

DE 040 28 605 discloses an illuminating device for an operatingmicroscope with an illuminating system that is arranged outside theoptical axis of the microscope objective and illuminates the operatingarea parallel to the axis of the objective through the microscopeobjective, and a deflector element on the side of the microscopeobjective remote from the object, which illuminates the operating areawith a fraction of the illuminating light along the axis of theobjective. This illuminating device is characterised in that theilluminating system is equipped, on the objective side, with areflecting element which reflects the illuminating light parallel to theobjective axis towards the microscope objective, and in that thedeflector element illuminates the operating area at an angle ofinclination relative to the objective axis that is smaller than theangle of inclination at which the reflecting element illuminates theoperating area. The larger angle of inclination is preferably 6°, thesmaller angle is variable from 0° to 6°. The illuminating devicedescribed in this publication does not contain any solution forproviding, for example, a red reflex for a second observer (assistant).

DE 103 11 000 B4 discloses an illuminating device for a microscopehaving at least one observation beam path, particularly an operatingmicroscope, with an illuminating system and a deflector device fordeflecting light emanating from a light source onto an object that is tobe observed, e.g. an eye that is to be operated on, the deflector deviceproviding illumination of the object at different illuminating angleswith respect to the at least one observation beam, and the deflectordevice comprising two deflector elements that are at least partlyconfigured as physical beam splitters. This illuminating device usesthree deflector elements to provide a 6° and a 2° illumination for amain surgeon and an assistant.

An illuminating device is known from DE 102 08 594 in which, in oneembodiment, two parallel illuminating beam pencils are used. These aredeflected from deflector elements with a total mirror finish. Because ofthe total mirror finish these deflector elements cannot be placed in theobservation beam paths, which means that certain minimum angles betweenthe optical axis of a main objective or the observation beam paths andthe illuminating beam paths are unavoidable. However, to provide theoptimum red reflex, the angles should be as small as possible.

SUMMARY OF THE INVENTION

The present invention seeks to provide an illuminating device for anoperating microscope that is as simple as possible, of compact designand cheap to produce, and which provides both a first observer (mainoperator) and a second observer (assistant) with an optimised red reflexat the same time. This aim is achieved with an illuminating devicehaving two semitransparent deflector elements, a first of which isassociated with a first observation beam path of the first observer anda first observation beam path of the second observer, and a second ofwhich is associated with the second observation beam path of the firstobserver and the second observation beam path of the second observer. Incorresponding manner, a compact stereomicroscope, particularly anoperating microscope, can be provided by means of the invention.

As a result of the inventive feature of providing two semitransparentdeflector elements, a first of which is associated with a firstobservation beam path of the first observer and a first observation beampath of the second observer, and a second of which is associated withthe second observation beam path of the first observer and the secondobservation beam path of the second observer, first of all the number ofdeflector elements required can be minimised. By the term “associated”is meant, in particular, that the respective deflector elements overlapthe observation beam paths assigned to them at least partly and moreparticularly completely, i.e. the observation beam paths intersect withthe deflector elements with part of their pencil cross-section.Moreover, the fact that each of the two illuminating beam paths is madeavailable partly to the first observer and partly to the second observerensures that the red reflex is of substantially the same quality forboth observers. Furthermore, thanks to their semitransparency, thedeflector elements used according to the invention can be positionedanywhere in the observation beam paths, without any adverse effects forthe observers. In particular, this measure provides zero degreeillumination, with which an optimum red reflex is obtained.

The further feature according to the invention that the firstilluminating beam path acts exclusively on the first deflector element,and the second illuminating beam path acts exclusively on the seconddeflector element, i.e. each of the parallel illuminating beam pathsacts on only one deflector element, ensures that undesirable lightreflexes and/or reflections are substantially avoided within themicroscope. In particular, crosstalk between individual channels of theoperating microscope can be effectively prevented.

In all, as will require no further explanation, the two observation beampaths of the main surgeon are used for stereoscopic viewing by the mainsurgeon, and the two observation beam paths of the assistant are usedfor stereoscopic viewing by the assistant.

The orientation of the illuminating beam paths relative to the deflectorelements can also be described in terms of the stereo base of the mainsurgeon or assistant. The (parallel) observation beam paths of the mainsurgeon define the stereo base of the main surgeon by their spacing fromone another. Analogously, the (parallel) observation beam paths of theassistant define the stereo base of the assistant. As already mentioned,the deflector elements each serve to illuminate one observation beampath of the main surgeon and one observation beam path of the assistant.

A line passing through these two observation beam paths represents thelongitudinal axis of the respective deflector element. The presentinvention is characterised in that the stereo bases of the main surgeonand assistant run diagonally with respect to these longitudinal axes ofthe deflector elements, particularly at an angle of 30°-60°, preferably45°.

This deviation from conventional illuminating beam path allocationsmakes it possible according to the present invention to operate twoobservation beam paths of a main surgeon and two observation beam pathsof an assistant with only two deflector elements. This results inparticular in an optimum red reflex for both the main surgeon and theassistant. Moreover, an illuminating device that requires only twodeflector elements for the stated purpose is very compact in itsconstruction. It has also proved advantageous that the illuminating beampaths striking the deflector elements can be shone in diagonally withrespect to the imaginary lines joining the two observation beam paths ofthe main surgeon and of the assistant, respectively.

Advantageous embodiments of the invention are the subject of thedependent claims.

According to a preferred embodiment of the illuminating device accordingto the invention, the illuminating system used, by means of which thedeflector elements are acted upon with light, has a single light source.A light source of this kind may cooperate with a beam splitter elementsuch as a Köster prism such that two suitable parallel illuminating beampaths can be produced. Alternatively, bundles of fibres proceeding fromthe light source may be used to provide the respective illuminating beampaths. Two or more independent light sources may also be used.

It is preferable if the two deflector elements used according to theinvention serve to provide 0° to 2° illumination for the first andsecond observer.

Expediently, the illuminating device according to the inventioncomprises at least one additional deflector element for providingfurther illumination at a greater angle, particularly illumination ofthe surrounding area (peripheral illumination) or 6° illumination.Because of the compactness of the 0° or 2° illumination which requiresonly two deflector elements according to the invention, furtherdeflector elements for the 6° illumination can be arranged particularlyeasily and flexibly. An additional deflector element of this kind may beacted upon by an illuminating beam path which runs substantiallyparallel to the first and second illuminating beam paths, while in thiscase the additional deflector element has substantially the same spatialorientation as the first and second deflector elements. It is alsopossible to configure an additional illuminating beam path at an angle,for example substantially perpendicular, to the first and secondilluminating beam paths, the additional deflector element in this casehaving a correspondingly different spatial orientation.

The first deflector element and the second deflector element areconveniently at substantially the same spacing from a main objective,onto which they deflect the light received from the illuminating system.This embodiment is very compact in construction, particularly in thevertical or perpendicular direction.

In a preferred embodiment, it is also possible to arrange the thirddeflector element at the same height as the first and second deflectorelements. By this means it is also possible to produce an illuminatingsystem that provides 0° or 2° illumination and 6° illumination in a verycompact manner.

The additional deflector element may also be configured as asemitransparent (partly transparent) reflecting element and/or as an atleast partly fully mirrored reflecting element. When a semitransparentreflecting element is used it is possible in particular to illuminateanother beam path, for example for documentation (as a third observationoption in addition to the main surgeon and assistant), while supplying ared reflex. The use of a fully mirrored reflecting element allowsparticularly effective illumination.

According to another preferred embodiment of the illuminating deviceaccording to the invention, the first and/or second deflector element isfully mirrored at least in parts. By this means, areas of the deflectorelements located outside the projection of the observation beam paths,for example, can be configured to be fully mirrored without affectingthe observation beam paths. It is also possible for example to constructsmall areas of the deflector elements that are located within theprojection of the observation beam paths or are acted upon by them witha full mirror finish. As a result the red reflex can be positivelyinfluenced, for example, without the observer noticing the fullymirrored areas within the observation beam paths.

Expediently, the illuminating device according to the inventioncomprises a device for reducing unwanted light reflexes and/orreflections within the operation microscope. Using a device of thiskind, in particular, crosstalk between individual channels of theoperating microscope can be further minimised. Reference should be madeat this point to the use of light traps, in particular.

According to another preferred embodiment, the first and the seconddeflector elements are formed in a unified glass block. Mounting them ina glass block in this way serves to reduce unwanted reflexes orreflections, as glass-air surfaces which may produce unwantedreflections of this kind are minimised.

It is also advantageously possible to construct the first deflectorelement and the second deflector element by means of a semitransparentreflecting element. This semitransparent reflecting element may haveopaque regions to distinguish the illuminating beam paths from oneanother. It may also have fully mirrored regions, particularly outsidethe observation beam paths that run through it. The red reflex can befurther optimised by these fully mirrored areas, as already mentioned.

Further advantages will become apparent from the description of theattached drawings.

It will be understood that the features mentioned above and those stillto be explained hereinafter may be used not only in the particularcombination stated but also in other combinations or on their ownwithout departing from the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWING VIEWS

The invention will now be explained further by a description ofpreferred embodiments with reference to the attached drawings.

In the drawings

FIG. 1 is a plan view of a first preferred embodiment of an illuminatingdevice according to the invention,

FIG. 2 is a schematic side view of the illuminating device in thedirection of the arrow P according to FIG. 1, and

FIG. 3 is a plan view of another preferred embodiment of an illuminatingdevice according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

In FIGS. 1 and 2, a preferred embodiment of the illuminating deviceaccording to the invention, comprising a main objective 150 and,downstream thereof, a magnification system (including the requisitetubes and eyepieces) 160 of a microscope 300, is generally designated100.

The microscope 300 is an operating stereomicroscope which provides twoobservation beam paths 152, 154 for a main surgeon and two furtherobservation beam paths 156, 158 for an assistant. The observation beampaths running in corresponding observation channels are represented inFIG. 1 as circles and in FIG. 2 by means of the observation axes 152 a,154 a, 156 a, 158 a associated therewith. There is no need to go intodetail about specific items of equipment (such as e.g. lenses and zoomsystems) for providing four such observation channels within the scopeof the present invention relating to an illuminating device.

The illuminating device 100 according to the invention first of all hasa light source 102. Two parallel illuminating beam paths 106, 108 aregenerated by means of a beam splitter 104 (diagrammatically shown inFIG. 1), which may be configured as a Köster prism, for example. As willbe self-explanatory, these illuminating beam paths 106, 108 may beregarded as light beams emanating from (virtual) light sources 106 a,108 a. It is also possible to provide two (actual) light sources 106 a,108 a instead of the light source 102 and beam splitter 104. The use offibre illuminating devices is also possible.

The illuminating device 100 also comprises two deflector elements 118,120 as a deflector device.

The first deflector element 118, which the illuminating beam path 106strikes first, is configured as a semitransparent element (physical beamsplitter), particularly a semitransparent mirror. The second deflectorelement 120 that the illuminating beam path 108 strikes is ofcorresponding construction, for example again in the form of asemitransparent mirror. It is possible to construct areas of thedeflector elements 118, 120, for example regions located outside or inthe edge region of the observation beam paths, with a full mirrorfinish. It is also possible for example to construct small areas of thedeflector elements in the centre of the observation beam paths, i.e.substantially within the region of the observation axes, with a fullmirror finish. This measure allows the red reflex to be influenced, forexample.

The deflector elements 118, 120 or their longitudinal axes which can bedefined as the connecting lines between the observation axes of theirassociated observation beam paths, are oriented diagonally or at anangle of 45° to the main surgeon's stereo base (imaginary connectingline between the observation axes 152 a, 154 a of the main surgeon) orthe assistant's stereo base (imaginary connecting line between theobservation axes 156 a, 158 a of the assistant). The deflector elementsare arranged in the immediate vicinity of the optical axis 151 of themain objective 150 and thus close to the observation axes 152 a, 154 a,156 a, 158 a, and therefore provide a 0° or 2° illumination of theobject 200 for each observation beam path.

The illuminating device also comprises another deflector element 170which is acted upon by another light source 172. The deflector element170 is arranged at a greater distance from the optical axis 151 of themain objective 150 and serves to provide a 6° illumination for theobservation beam paths 152, 154, 156, 158, which is advantageous forincreasing the contrast for users of the microscope. For operatingtechniques in which the red reflex is not required, it may be sufficientto use only the 6° illumination. The deflector element 170 is preferablyconfigured as a fully mirrored reflector, and also arranged at an angleof 45° to the preferably horizontally extending additional illuminatingbeam path 174. It is possible to combine the light sources 102, 172 toform a single light source, and to produce the illuminating beam paths106, 108, 174 by means of suitable beam splitter devices and/or lightconducting systems (fibre optics).

It is also possible to make the deflector element 170 semitransparent,so that an additional observation beam path 179 (shown by dashed lines)can be illuminated. A documentation device, for example, may beconnected to this observation beam path 179. For the observation beampath 179, a 0° to 2° illumination is thus provided, for example,rendering the red reflex visible even within the scope of thedocumentation, as no light whatsoever has to be coupled out of theobservation beam paths for the documentation.

The core of the invention lies in the particular arrangement of thedeflector elements 118, 120 relative to the observation beam paths 152,154 of the main surgeon and 156, 158 of the assistant:

As can be seen from the Figures, the first deflector element 118 isassociated with the first observation beam path 154 of the main surgeon,and the first observation beam path 156 of the assistant. This meansthat the horizontal projection of the deflector element 118, as shown inFIG. 1, at least partially overlaps the first observation beam path 154of the main surgeon and the first observation beam path 156 of theassistant. This overlap can be selected as desired, while in particulara total overlap is also possible. The illuminating beam path 106 ispartly deflected through 90° by the first deflector element 118 in thedirection of the main objective 150 (partial beam paths 106′), andpartly transmitted without any deflection (partial beam path 106″).

The partial beam path 108 strikes the second deflector element 120analogously, this second deflector element being associated with thesecond observation beam path 152 of the main surgeon and the secondobservation beam path 158 of the assistant. The second deflector element120 is also of semitransparent construction. The partial beam pathdeflected through 90° in the direction of the main objective isdesignated 108′, and the transmitted partial beam path is designated108″.

The transmitted partial beam paths 106″, 108″ expediently strike a lighttrap 171 (not shown in detail) to minimise unwanted reflections.

The illuminating system shown thus provides both the main surgeon andthe assistant with an optimum red reflex, and achieves this with onlytwo deflector elements 118, 120 and preferably only one light source102.

According to the embodiment shown in FIGS. 1 and 2, the two deflectorelements 118, 120 are arranged at the same height relative to theoptical axis 151. The same is true of the additional deflector element170. This measure advantageously makes it possible to minimise theoverall height of an operating microscope equipped with the illuminatingdevice according to the invention. It is also possible to mount thedeflector elements 118, 120 in an offset position relative to theoptical axis 151, i.e. at different heights. Two deflector elements thusoffset from one another in the vertical direction can also be acted uponby only a single light source using a corresponding beam splitter.

The deflector elements 118, 120 may be provided in a coherent glassblock (not shown). In this way the number of glass-air surfaces can bereduced, thus further reducing unwanted reflections. The deflectorelements 118, 120 may also be constructed as a single reflectingelement, while opaque regions may be provided between the deflectorelements 118, 120 which are of semitransparent construction according tothe invention. These opaque regions may be configured to be fullyabsorbent or fully mirrored. Using these measures, the illuminatingbeams striking the object that is to be observed can be delimited fromone another or shaped in any desired manner. It is possible for exampleto provide illuminating beam paths of rectangular, square or roundcross-section.

Cross-sections of illuminating beam paths of this kind may also beobtained by a suitable choice of the lighting medium of the lightsource, with particular reference to halogen lamps, LEDs, etc.

FIG. 3 is a plan view of a particularly preferred embodiment of theilluminating device according to the invention viewed in schematic planview. The same or similar components have been given the same referencenumerals here. Beam paths emanating from a light source 102 are split bya beam splitter element 104 into illuminating beam paths 106, 108. Theelement 104 is embodied here as a semitransparent mirror. Theilluminating beam path 106 is deflected again from another, fullymirrored element 104 a, so that the illuminating beam paths 106, 108then run parallel to one another again. The illuminating beam path 106strikes the first semitransparent deflector element 118, theilluminating beam path 108 strikes the second semitransparent deflectorelement 120. The respective observation beam paths which aresubstantially overlapped by these deflector elements 118, 120 are notshown here.

Another light source for providing illumination of the surrounding areais designated 172. This acts on an additional deflector element 180,which may be semitransparent or fully mirrored, with anotherilluminating beam path 174. The embodiment shown in FIG. 3 ischaracterised in that both the illuminating beam paths 106, 108 neededfor the red reflex illumination and the illuminating beam path 174 usedfor illuminating the surrounding area are irradiated from substantiallythe same direction, i.e. substantially parallel to one another. Thisresults in a particularly compact construction.

What is claimed is:
 1. An illuminating device for an operatingmicroscope, the operating microscope having a main objective, twoobservation beam paths for a first observer and two observation beampaths for a second observer, the illuminating device comprising: anilluminating system for providing two parallel illuminating beam paths;and a deflecting device arranged to deflect the parallel illuminatingbeam paths onto an object to be observed by the microscope; wherein thedeflecting device includes a first semitransparent deflector elementassociated with a first observation beam path for the first observer anda first observation beam path for the second observer, and a secondsemitransparent deflector element associated with a second observationbeam path for the first observer and a second observation beam path forthe second observer, the first illuminating beam path acting exclusivelyon the first semitransparent deflector element and the secondilluminating beam path acting exclusively on the second semitransparentdeflector element.
 2. The illuminating device according to claim 1,wherein the illuminating system comprises only one light source.
 3. Theilluminating device according to claim 1, wherein the first and secondsemitransparent deflector elements are arranged to illuminate the objectat a first illuminating angle relative to the observation beam paths for0° to 2° illumination for the first and second observers.
 4. Theilluminating device according to claim 3, further comprising anadditional deflector element arranged to illuminate the object at asecond illuminating angle greater than the first illuminating anglegreater relative to the observation beam paths.
 5. The illuminatingdevice according to claim 4, wherein the additional deflector elementprovides illumination of an area surrounding the object or 6°illumination of the object.
 6. The illuminating device according toclaim 1, wherein the first semitransparent deflector element and thesecond semitransparent deflector element are at the same distance fromthe main objective of the microscope.
 7. The illuminating deviceaccording to claim 4, wherein the additional deflector element isarranged at the same height as the first and second semitransparentdeflector elements.
 8. The illuminating device according to claim 1,wherein the first and second semitransparent deflector elements aresemitransparent mirror elements.
 9. The illuminating device according toclaim 4, wherein the additional deflector element is a semitransparentmirror element.
 10. The illuminating device according to claim 4,wherein the additional deflector element has a portion that is fullymirrored.
 11. The illuminating device according to claim 10, wherein theadditional deflector element provides an additional observation channel,whereby a documentation device may be connected to the microscope. 12.The illuminating device according to claim 1, wherein at least one ofthe first and second semitransparent deflector elements has a portionthat is fully mirrored.
 13. The illuminating device according to claim1, further comprising a light trap arranged to prevent unwantedreflections within the microscope.
 14. The illuminating device accordingto claim 1, wherein the first and second semitransparent deflectorelements are formed in a unified glass block.
 15. A stereomicroscopecomprising: a main objective; a magnification system downstream from themain objective; two observation beam paths for a first observer and twoobservation beam paths for a second observer; an illuminating system forproviding two parallel illuminating beam paths; and a deflecting devicearranged to deflect the parallel illuminating beam paths onto an objectto be observed by the stereomicroscope; wherein the deflecting deviceincludes a first semitransparent deflector element associated with afirst observation beam path for the first observer and a firstobservation beam path for the second observer, and a secondsemitransparent deflector element associated with a second observationbeam path for the first observer and a second observation beam path forthe second observer, the first illuminating beam path acting exclusivelyon the first semitransparent deflector element and the secondilluminating beam path acting exclusively on the second semitransparentdeflector element.